What is the formula to convert CPM to DPM?

The conversion from counts per minute (CPM) to disintegrations per minute (DPM) involves accounting for the detection efficiency of the system. The detection efficiency refers to the proportion of actual disintegrations that are detected as counts.

The process starts with measuring the gross counts, which represent all detected radiation events, and then subtracting the background counts to account for any extraneous radiation that could interfere with the true signal from the sample of interest. This gives a net count rate that reflects only the relevant emissions.

The result, which is the net CPM, is then divided by the system's efficiency (expressed as a decimal) to translate the count rate into the actual disintegrations occurring in the sample, giving the DPM value. Thus, the formula logically follows the principles of radiation detection and quantifies the true disintegration rate based on the effective measurements obtained.

This formula is critical as it ensures that the data reflects an accurate assessment of the radioactivity present, corrected for any detection inefficiencies and background noise.